Impact of Stefan flow on the interphase scalar transfer in flow past random particle arrays

By using a particle-resolved direct numerical simulation, the impact of Stefan flow on interphase heat transfer in flow past static random particle arrays is investigated. The findings demonstrate that the temperature boundary layer of particles is thickened/thinned by the outward/inward Stefan flow and therefore hinders/improves the contact between main gas flow and particles. With the impact of positive Stefan Reynolds number (Resf), the maximum percentage reduction of Nusselt number could be over 3 times of the maximum percentage reduction of drag coefficient at the same condition. The rise in particle Reynolds number (Re) or solid volume fraction (c) can partially offset the impact of Stefan flow. Finally, the simulation data are used to develop a correction factor for interphase heat transfer considering the impact of Stefan flow for-3 < Resf < 6, 0 < Re < 100, and 0 < c < 0.5. Note that the scalar in current work is chosen to be the dimensionless temperature, but the results are general and applicable to any passive scalar.

Automated summary

Using particle-resolved direct numerical simulation, this study investigates the impact of Stefan flow on interphase heat transfer in flow past static random particle arrays. The results show that outward/inward Stefan flow thickens/thins the temperature boundary layer of particles, which hinders/improves the contact between main gas flow and particles. The positive Stefan Reynolds number (Resf) can cause a greater reduction in the Nusselt number compared to the maximum reduction in the drag coefficient under the same conditions. However, an increase in particle Reynolds number (Re) or solid volume fraction (c) can partially offset the impact of Stefan flow. A correction factor for interphase heat transfer considering the impact of Stefan flow is developed based on the simulation data for-3 < Resf < 6, 0 < Re < 100, and 0 < c < 0.5. It is important to note that the scalar chosen in this study is dimensionless temperature, but the results can be applied to any passive scalar.